Enhance mailbox permission modification and bulk request tracking

Refactored Invoke-ExecModifyMBPerms.ps1 to support multiple mailbox request formats, improved error handling, and implemented precise result mapping using operation GUIDs for bulk permission changes. Updated New-ExoBulkRequest.ps1 to propagate and track operation GUIDs through batch requests, enabling accurate correlation of results and errors to specific permission operations.

Author: Zacgoose